Medical liquid administration device

ABSTRACT

Positive pressure apparatus for providing an adjustable and reliably constant delivery rate of medical liquids from parenteral applicators, including a self-contained portable medical liquid administration device wherein precisely regulated gas flow through a first flow restrictor operates to pressurize and cause to flow at a substantially constant rate a liquid from a supply through a second flow restrictor which has a flow/pressure drop characteristic such that the liquid flow is essentially independent of gravity-induced pressure fluctuations.

mte States Patent 1151 3,64,277 Adelberg Feb. 8, 1972 [54] MEDICAL LIQUADMINISTRATION 3,298,367 1/1967 Bergman ..128/2l4 DEVICE 3,468,3089/1969 Bierrnan ....128/214 3,486,539 12/1969 Jacuzzi ....222/386.5

[ lnvenwfl Marvin Adelbers, 4043 y Road, Sher- 1,617,614 2/1927 York..13s/45 x man Oaks, Calif- 9140 1,869,443 8/1932 Stocklin ...l28/2152,541,464 2/1951 Davies ..91/31 [22] 1968 2,642,867 6/1953 Livingston....128/214 [21] Appl. No.: 782,399 2,693,801 11/1954 Foreman......128/214 3,081,942 3/1963 Maclay ..91/31 [52] US. Cl. ..l28/214 1F,128/D1G. 12, 138/45, P Em Dalt L T I k 222/61, 222/386.5, 222/399,73/228 ZZZQ ZZ'SM 23 m [51] lint. Cl. ..A6lm 05/00 [58] Field ofSearch..222/94, 95, 61, 386.5, 399; [57] ABSTRACT 91/31 Positive pressureapparatus for providing an adjustable and reliably constant deliveryrate of medical liquids from parenteral [56] References Citedapplicators, including a self-contained portable medical liquidadministration device wherein precisely regulated gas flow UNITED STATESPATENTS through a first flow restrictor operates to pressurize and causeto flow at a substantially constant rate a liquid from a supply2,761,445 9/1956 Cherkm ..12s/214 through a second new restrict), whichhas a flow/pressure 2,766,907 10/1956 Wallace ..222/94 dropcharacteristic Such that the liquid flow is essentially i 3042'0867/1962 128/214 X pendent of gravity-induced pressure fluctuations.

3,048,171 8/1962 Grau 128/214 2 3,054,401 9/ 1962 Gewecke ..128/214 28Claims, 19 Drawing Figures PATENTED FEB 8 i972 SHEET 3 BF 3 MEDICALLIQUID ADMINISTRATION DEVICE BACKGROUND OF THE INVENTION 1. Field of theInvention This invention is concerned with improvements in theadministration of medical liquids to patients veins, arteries, and otherportions of the body. More particularly the invention provides a devicefor such administration which is essentially independent of gravity andalso assures a uniform flow rate.

2. Prior Art The administration of medical liquids is largely carriedout by gravity-induced hydrostatic pressure infusion of the liquid froma bottle or other container suspended above the recipient an acceptabledistance. The flow rate is not easily controlled since variations inrelative positions of the receiving portion of the patient and thedispensing bottle may occur with time as the patient or bottle may beshifted about.

Moreover, previously available pressure-assisted administration devicesfor carrying out intravenous infusions are quite complicated and, whenemployed, relatively expensive. Previous devices have lacked portabilityand simplicity. Thus, should a patient require relocation such as froman operating to a recovery room, or from a field emergency unit to apermanent hospitaLspecial, costly and awkward means such as anadditional attendant are required. In other cases, such as for cardiacor infant patients, the desired flow rate must prescribed accuratelycontrolled or even deliberately changed from one prescribed rate toanother.

In previously known pressurized delivery devices, various sources ofpressure including gas and liquid have been used to pressurize a supplyof medical liquid to be administered. For example in US. Pat. No.3,044,663 to Norton et al. an auxiliary pressure supply means such as apump, air pressure tank or gas cartridge is disclosed to be useful indisplacing liquid from a container. Similarly, in US. Pat. No. 2,842,123to Rundhaug a collapsible liquid supply is pressurized for subsequentdelivery of liquid. In these. devices provision for control of flow ofthe administered liquid is either absent, as in Norton, or operatoradjusted as in Rundhaug, either of which can result in unpredictableflow rate conditions depending on the reliability of the pressure supplyand/or the skill and attention of the operator.

SUMMARY OF THE INVENTION It is a major objective of this invention toprovide for positive, gravity independent control to a medical fluiddelivery system in which a selected flow rate is provided and maintainedat all times.

Briefly, and in general terms, the present invention provides, in amedical liquid administration system, means for providing a first fluidat a regulated, constant flow rate to selectively, reliably, andaccurately displace a second fluid and cause the second fluid to alsoflow at a substantially constant flow rate. The invention may alsoinclude means for minimizing the effects of gravity-induced hydrostaticpressure upon flow of the second fluid, and may further include meansfor filtering the second fluid during pressurized flow. One fea ture ofthe present invention relates to a new and improved structural assemblyincorporating a container for the second fluid together with combinedmeans for filtering the fluid and minimizing fluid flow due to normallyencountered levels of gravity-induced hydrostatic pressure.

Accordingly the invention provides a medical fluid administration devicewhich includes a supply of medical liquid and fluid passage mans forconnecting the liquid supply to a recipient. A flow-restricting means isprovided within the The medical (second) liquid may be carried in apressurecollapsible container for displacement by a compressed gas(first liquid) operating thereon for pressure displacing of the secondliquid therefrom.

Thus there may be provided in accordance with the invention a medicalfluid administration device which includes a container for medicalliquid having a collapsible volume and a liquid outlet, and connectormeans defining a liquid passageway from the container outlet, thepassageway terminating in or with an applicator. A flow restrictor ismounted within the passageway, the restrictor having a fixed-flowchannel, to permit the desired flow of liquid when subjected to apressure exceeding that induced by gravity. Pressurizing means isprovided for contracting the volume of the container to expel the liquidtherefrom at a predetermined pressure, including a controllablyreleasable high-pressure fluid supply.

Valve means are provided for controlling pressure and flow rate of thedriving fluid, the latter preferably being achieved through use of aporous plug in the passageway providing narrow and tortuous flow pathsof great efi'ective length relative to the axial flow path through theplug. A plurality of such plugs may be provided, each providing adifferent effective flow rate/pressure drop characteristic and mountedfor al ternate registration with the driving fluid passageway. Furtherll features include quick-fill means for rapidly pressurizing thecontainer at the desired pressure level.

The pressurizing means may further include a variablevolume drivingfluid receiver in pressure transmitting contact with the driven orsecond fluid container which cooperates with contracting means tocontract the second fluid container upon a corresponding increase in thevolume of the driving fluid receiver. The contracting means may take theform of inextensible material partially or totally circumscribing thevolume of the second fluid container. and the first fluid receiverwhereby an increase in volume of the first fluid receiver decreases thevolume of the second fluid by a corresponding amount. The first fluidreceiver and second fluid container may be each formed separately ofthin inextensible plastic sheeting or be formed thereof with a commonwall. In either event a rigid frame may surround the receiver andcontainer to define their maximum combined volume and to protect themfrom external disturbances.

Still other features include provision of means associated with thedriving fluid supply in a manner to meter predetermined amounts of thisfluid corresponding to a quantity of second fluid to be displaced fromthe container and means for indicating occurrence of flow in the secondfluid passage means at a portion thereof which is transparent. Suchindicating means may also indicate flow rate.

Currently desired micron-sized particle filtering of medical liquids iseasily accomplished by the present invention, because of the higherpressures available, in a medical liquid administration device in whichthe driven fluid flows from a supply thereof along a passageway into auser, by provision of means for filtering minute foreign solid materialfrom this fluid in the passageway.

These and other objects and advantages of the invention, as well as thedetails of illustrative embodiments, will be more fully understood fromthe following description and drawings.

BRIEF DESCRIPTION 'OF DRAWINGS FIG. I is a diagrammatic representationof a system incorporating the invention;

FIG. 2 is a table illustrating pressure conditions in FIG. 1;

FIG. 3 is a graph of fill pressure versus time;

FIG. 4 shows one form of flow restrictor selector apparatus;

FIGS. 58 are sections illustrating various forms of gas and liquiddefining zones usable in the FIG. 1 system;

FIG. 5a is an end view of the FIG. 5 housing;

FIG. 9 is a perspective showing advantageous packaging of the invention;

FIG. 10 is an end view of the FIG. 9 package;

FIG. 11 is an enlarged section taken through the flow restrictor rotaryselector of FIG. 9;

FIG. 12 is a section taken on line 12-12 of FIG. 11; FIG. 13 is anenlarged section taken on line 13-13 of FIG.

FIG. 14 is a section showing a flow indicator; FIGS. a and 15billustrate another flow indicator; FIG. 16 is a section showing amodified indicator; and, FIG. 17 is a section showing a check valve.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, theillustrated system includes a driving fluid contained in a pressurereservoir 10 the outlet of which is connected at 11 to the inlet of apressure regulator 12. The reservoir 10 may for example consist of asmall bottle of two-phase (liquid-vapor) carbon dioxide or otherhighpressure fluid, as a source of driving energy. The pressureregulator 12 reduces the pressure of the driving fluid from a lever p toa level p as indicated, and the latter may be varied within limits byadjustment of the regulator control 13. Normally, p is much less thanp,, as is stated in the FIG. 2 table of preferred conditions.

The fluid at pressure p then flows via connection 14 to and through aflow restrictor R FIG. 1 showing several of same grouped at 15 andindividually labeled at 15a, 15b, and 150.

Merely for purposes of illustration, inlet valves are indicated at 16a,16b and 160 as operable to control the flow to pass to and through anyof the restrictors. The latter permit different flow rates correspondingto the pressure setting 17;. Such flow rates may vary over a wide range;and the design of the restrictors may be made to accommodate that rangeas by varying the lengths or cross-sectional areas, or both, of therestrictors as well as choosing materials of different porosity. FIG. 4shows three restrictors 15a, 15b and 150 of different lengths inparallel passages 17a, 17b and 170 formed in a block 18. A valve unit 20having branches 21 and 22 is movable relative to the block toselectively register passages 23 and 24 in those branches with thepassages 17a-l7c. Preferably valve unit 20 is rotary, and one form ofrotary unit will be described subsequently.

As referred to, it is the purpose of the flow restrictors R, to set theuniform rate of flow Q (usually) very low) of the driving fluid flowingat 33 to a zone wherein contained pressure 12 is operable to drive fluidfrom a fluid zone 31 at uniform rate, the rate Q being primarilydetermined by the pressure drop (p -p across the restrictor RAccordingly, there are different rates of flow Qa, Qb and 00 forexample, associated with the different restrictors 15a, 15b and 150.Intermediate flow rates may be obtained by adjusting the control 13 onthe pressure regulator 12, which may for example adjust the springtension in the regulator. The latter may be of spring and diaphragmtype, and one example is that known commercially as Model 1 1-039,manufactured by The Norgren Company of Littleton, Colo. The regulator issuch that 2 is maintained despite large changes in p,, whereby the flowrate is kept uniform; however, the sizes or capacities of reservoir 10and zone 31 may be so related that the reservoir exhausts just beforezone 31 becomes exhausted, providing automatic shutoff.

The flow restrictor or restrictors R may, for example, consist ofceramic material or sintered metal, both of which are porous. Whileneedle valves could be used, they tend to be contamination sensitive atlow flow rates, and are not preferred. Note also the use of safetyvalves 32 and 32a connected to lines 11 and 33 in FIG. 1. Valve 32 isopened to relieve remaining pressure in reservoir 10, in response toopening of a container indicated at 34 containing fluid zone 31, inorder to insure that the reservoir 10 cannot be reused without replacingwith a full unit. Also, reservoir 10 may take the form of a metalcartridge which may be automatically disconnected from line 11 as byretractor 36 in response to opening of the container 34. Safety valve32a operates to relieve pressure in line 33 should it inadvertentlyexceed a preset level.

Reference to FIG. 5 shows that the preferred driving and driven fluidzones are formed by separate and abutting collapsible containers 40 and41, respectively, having a large common interface. These are housedwithin a rigid container or frame having upper and lower sections 42 and43. The upper section may be removed to permit removal of an exhausteddriven fluid container and insertion of the new driven fluid container41 over the driving fluid container 40, which is typically, at suchtime, in a deflated state or caused to be deflated by opening valve 32a.It then becomes necessary to rapidly fill driving fluid into thedeflated container 40 so that normal flow of driven fluid from container41 may be resumed or commenced. Such driven fluid flow passes via line44 containing flow restrictor R to a tip 45 (such as a needle) fordelivery.

FIG. 1 illustrates a highly advantageous quick-fill system which may beused to rapidly fill zone 30, i.e., container 40 in FIG. 5, with drivingfluid. As seen in FIG. 1, it includes flow restrictors R and R connectedin series at 46, restrictor R having its inlet connected at 47 to line14 via a valve 48. Similarly, line 46 is connected at 49 to the inlet tozone 30 via a valve 50. Finally, the outlet of restrictor R is connectedto atmosphere. The flow resistance r; of restrictor R is made much lessthan r of a selected operating restrictor R so that the driving fluidreadily flows via lines 47, 46 and 49 to the zone 30 when valves 48 and50 are open. Also, the flow resistance r, of restrictor R is so relatedto the r of restrictor R that the following relationship is established:

n/rF a/n in Under these conditions, the pressure p;, will increase froma value p to the operating value L in a short time 1,, as seen in FIG.3.

When a particular restrictor R, (15a-15c) is chosen to establish thedesired operating pressure p;,, a corresponding restrictor R (19a19c,respectively,) is selected (as by appropriate valving a-180c operativelyconnected to valving l6al6b[) to provide the proper flow resistance inaccordance with equation (I), so that the operating value L is rapidlyobtained.

FIGS. 6-8 show alternate forms of containers for the gas and liquidzones 30 and 31. In FIG. 6, a single flexible container 52 contains bothzones separated by a common pressure transmitting wall 53, and within arigid frame or enclosure 54. In FIG. 7 the liquid zone 31 is formed by aflexible container 540, and the gas zone 30 is formed between thatcontainer and the rigid, fluid tight enclosure 55. In FIG. 8 both gasand liquid zones 30 and 31 are open to the interior of container 56,with a gas-liquid interface at 56a. Automatic shutoff is important tothe latter to prevent unwanted feeding of gas such as carbon dioxide toa patient upon exhausting of liquid from zone 31. In all of these forms,the use of a rigid outer housing or frame enclosing zones 30 and 31 isimportant to prevent inadvertent squeezing of the containers (such as 40and 41 in FIG. 5), i.e., pressurization of the zones. Also, the fixedshape of the housing or frame defines limits of container pressurizeddisplacement to limit delivery of liquid to the outlet.

FIG. 1 also illustrates the provision of a gage to directly indicate therelative displacement status of the zones 30 and 31. Advantage is takenof the movement of interface 60 between the zones to indicate suchstatus, through use of a marker 61 driven by that interface (say up anddown) and adjacent to the calibration indicia 62. FIG. 5a shows anapplication of this in the FIG. 5 embodiment, wherein the end wall ofthe case or housing is slotted at 65 to pass the marker element 66 tothe exterior from the interior. The marker shank is held between thecontainers 40 and 41, as at interface 67, and there are calibrationmarkings on the housing to indicate the volume of fluid in the container42.

Referring back to FIG. 1, the apparatus illustrated is well adapted touse in administering parenteral or other solutions (as for exampleintravenous infusions) to an animal or human patient, and typically aneedle 45 is employed for this purpose. In such event R is constructedto provide a pressure drop (p p,,) sufficient in relation to gravityinduced hydrostatic head changes that might occur during administrationthat the latter changes are not of critical significance as respectsflow rate. (Such flow rate may be correlated with pressure and indicatedby the gage 70 connected in line 14, and suitably calibrated.) On theother hand, the pressure drop (p -p afforded by restrictor R, is muchgreater than the drop afforded by R As a consequence, flow rate isprimarily controlled by R,, and only secondarily controlled by R,,, butat the same time R assures that the gravity induced hydrostatic headfluctuations stemming from patient movement relative to the apparatus ofFIG. 1 and vice versa and will not affect the flow rate to anysignificant degree. Also, R may be constructed to provide filteringaction to insure delivery of fluid free of foreign particle contaminant.Such construction will be described later. By way of example only, thehydrostatic head fluctuations at the needle 45 would usually be lessthan one-half p.s.i., and the pressure 11 would usually exceed 3 p.s.i.

Finally, FIG. 1 illustrates the use of a shutoff and check valve 71 nearthe needle 45. Further, a bypass line 72 containing a valve 73 isconnected across the restrictor R for emergency use. The bypass directsthe flow in line 75 around R Altemately, provisions may be made for theemergency complete removal of restrictor R FIG. 9 shows elements ofanother form of medical liquid administration device as seen in FIG. 1.A container 100 formed of flexible inelastic plastic sheeting materialcontains medical liquid and overlies a gas receiving bag 1102 also ofplastic construction. The container and bag are located within anenclosing rigid frame or housing 103 having upper and lower sections 104and 105. The latter are hinge connected at 106 for convenience ininsertion and removal of successive medical liquid containers 100, andterminals 104a and 105a serve to hold them connectedThe container 100has an outlet 101 at an end thereof for discharge of the containercontents. Outlet 101 is fluid tightly connected to tubing 108 whichterminates at its opposite end in an applicator needle 120. Between theneedle 120 (or other device such as a catheter for administering fluids)and outlet 101, the tubing 108 is provided or bisected with a flowrestrictor filter 122, the construction and operation of which aredescribed in detail hereinafter, but which broadly has the function ofobstructing partially the passageway defined by tubing 108 to passagetherealong of liquids permitting desired flow rates only when drivingpressures are well in excess of those created by gravity and thuscooperating with the pressurizing system to be now described inproviding controlled administration of medical liquids.

The medical liquid-administering device herein is advantageouslyportable, compact and self-contained. Apressurized driving fluid supplymeeting these requirements is contained in a cartridge in which isstored liquefied CO fluorocarbons or hydrocarbons contained underpressures required to maintain liquid-gas equilibrium, or gases such asN under very high pressure. While other sources of gas may be usedherein, for maximum operating convenience, univer' sal commercialavailability and inherent portability, I prefer these cartridges. NoteFIG. 9 illustrates use of such a cartridge 124 encased in aclose-fitting mounting holder 126. The holder is provided at its upperend with a puncture tip conduit (not shown) adapted to receive,gastightly, the outlet neck of the cartridge in the well known manner.Pressure regulator 132, corresponding to that described at 12 in FIG.ii, is located as shown in FIG. 9, to be enclosed along with holder 126when cover section 104 is in the position seen in FIG. 10. Note also thelocation of the pressure gage 128 (corresponding to gage 70 in FIG. 1)at one end of the package, as seen in FIG. 10. Gage 128 connects toconduit 130. Note also the bounding walls 180-183.

The control of the rate of flow of driving fluid, which rate isdeterminative of the rate thereof entering driving fluid receiver 102and thus the rate of displacement of medical driven fluid into therecipient from container 100, is accomplished in conjunction with thedownstream driven fluid pressure (which is set by appropriate adjustmentof the pressure regulator 132) and also independently of normalvariations of the pressure downstream of the flow rate control point.This is achieved by the use of the flow limiting restrictor within acylindrical body having fixed end segments 140a and a rotatable center14%. These body segments may be fastened at 138 and sealed with ringseals 141, as seen in FIG. 11.

The flow rate restriction is obtained by passing the gas alongrelatively narrow paths within the valve body 140 which tend to impedegas flow. In the illustrated preferred embodiment, a porous plug 142 inpassage 144 is used as the gas-flow-restricting means, such plugproviding a multiplicity of narrow and tortuous paths for gas flowwhereby flow resistance is reliably controlled. Because various rates offlow may be desirable for different operating conditions, a plurality ofdriving fluid flow passages 144 may be provided for plugs 142 of varyingrestrictive characteristics. Thus, with reference to FIGS. 11 and 12 thecenter segment 140k of the valve body is bored to have passages 1144a,b, c and d therethrough. Passages 144a, b, and c are each provided witha gas flow restrictive porous plug 142 of different effective flowrate/pressure drop characteristic e.g., through difference inconstruction, diameter or, as illustrated, length of the plug wherebydifferent rates of gas flow may be had by rotation of the center segment1401) around fastener 138 to index one or the other of the passages tothe single bore continuation of conduit 130 in the end segments 14011.

A nonrestrictive flow passage 144d is provided as a bypass forunrestricted gas flow to rapidly provide gas pressure e.g., at startupof the device. In this regard, the quick fill bypass of FIG. 12 does notappear in the FIG. 11 sectional view. To insure against accident,separately actuable means are provided, best shown in FIG. 12 foractivating the quick fill. As there shown, the valve body segment 1411bis provided with a radial channel 146 in which there is positioned apush pin 148 having an enlarged outer end 148a for finger engagement anda reduced diameter inner end 150 axially slotted at 1500 to moveradially of the fastener 138 about which the valve segment 140!)rotates. Finger depression of the pin 148 against tension spring 152aligns aperture 154 of the pin with bypass passage 144d for quick fillgas flow. Inadvertent depression of the pin 48 may be prevented by asuitable lock (not shown) which may be gas pressure operated.

A further safety feature as seen in FIGS. 10 and 11 is found in theprovision of a relief valve in conduit 131 which is set to insure nogreater than some predetermined pressure, this valve corresponding tothat seen at 32a in FIG. 1.

Having described the pressurizing means to include illustratively asource of positive pressure such as and preferably a miniature liquefiedgas cylinder or cartridge, a pressure regulator and a gas flowrestrictor combination which operates independent of normal variationsof downstream gas pressure, reference is now made to FIGS. 9 and 13 forthe ensuing discussion of the driven fluid flow restrictor aspect of theinvention.

To remove operator error as a source of difficulty, the present deviceemploys a fixed-flow-channel-type restrictor. For this purpose FIG. 13illustrates a ceramic porous cylindrical plug 162, which is thepreferred form of flow restrictor 122. Other flow-restricting devicesincluding porous plugs formed of other natural and/or syntheticmaterials, fused or bonded or otherwise held in rigid configuration maybe used. Membranous materials are generally insufficiently strong towithstand the applied pressures contemplated herein for satisfactoryperiods, but, if properly supported, may be employed.

A highly advantageous aspect of the use of finely porous plugs orsimilar type flow restrictor 122 is the opportunity to filter from theto-be-administered fluid foreign matter which occasionally is presenttherein. For this purpose channels 164 may have a size of 0.1 to 5microns or more or less, these values being illustrative.

Whatever the material of construction of flow restrictor 122, the flowrate/pressure drop characteristic is desirably controlled for particulareffects. For example, flow restrictors intended to have a filteringfunction may have a characteristic of less than 200 ml./hr./p.s.i., butthis only by way of example. Every flow restrictor, of course, will havea characteristic to reduce to small degree the significance of gravityon flow of fluid to the recipient.

Reference is now made to FIGS. 1 and 14 showing a flow indicator 79 inthe form of a thin disc 80 in the path of liquid flow in the line 75.The thin disc 80 includes a rigid stem 80a which is connected to one endof an elastic or springlike filament 81, the opposite end of which issuitably fixed in the line or tubing 75. As flow increases, the thindisc moves downstream, due to the elasticity or spring action asindicated by broken lines 82, and can be seen when the tubing istransparent. Calibrated indicia 83, mounted on and adjustable lengthwiseof the tubing 75, may be provided to afford flow rate information. Also,the downstream flow line may be temporarily clamped to see if disc 80snaps back, to confirm the existence of flow. FIGS. 15a and 15billustrate another flow indicator in the form of a thin disc 85 havingarigid stem 85a secured to one end of an inelastic filament 86. As flowcommences, the disc 85 oscillates in the tubing, as between FIG. 15a and15b positions, higher frequency indicating greater flow rates. FIG. 16shows a combination of the FIG. 14 and 15 concepts, and wherein the discelement 80a stretches on spring element 81a to show flow rate; and inaddition the oscillator element 85a oscillates on filament 86 (mountedon disc 80a) to confirm the existence of flow. The thin disc elements 85and 85a may take other forms, e.g., small spheres, cylinders, groovedcylinders so long as there is clearance between the tube and theelement. Also, the tubing containing the elements such as 85, 85a, 80and 80a should be circular and may consist of a short section of glasstubing. FIG. 17 illustrates a type of check valve 90 that may be used inline 75 near needle 45, to prevent back-flow. The valve has flaps 91which spread to pass flow to the right, but close together to blockreverse flow.

It will be apparent that appropriate alarm devices (not shown) may beutilized wherever system parameters are monitored, e.g., as at 70, 32a,62 and 79 in FIG. 1, to indicate malfunctions, unsafe, or undesirableconditions.

While particular forms of the invention have been illustrated anddescribed, various modifications can be made without departing from thespirit and scope of the invention. Accordingly, it is not intended thatthe invention be limited, except as by the appended claims.

Iclaim:

1. In parenteral liquid administration apparatus, the combinationcomprising:

a. container means having a first zone to receive a pressurized firstfluid and a second zone for a supply of a deliverable second fluid, saidzones extending in such confined and pressure-transmitting relation thatthe second fluid remains pressurized by the first fluid as the secondfluid zone diminishes and the first fluid zone expands; j

b. means to deliver said first fluid to said first zone and including afluid pressure regulator and variable flow restrictor means connected influid-flow-transmitting relation between said regulator and said firstzone; said flow restrictor means having selector means for providing apredetermined but variable pressure drop/flow rate characteristic; and

c. a conduit for delivering said second fluid for administration to apatient from said second zone.

2. In parenteral liquid administration apparatus, the combinationcomprising:

a. container means having a first zone to receive a pressurized firstfluid and a second zone for a supply of a deliverable second fluid, saidzones extending in such confined and pressure-transmitting relation thatthe second fluid remains pressurized by the first fluid as the secondfluid zone diminishes and the first fluid zone expands;

b. means to deliver said first fluid to said first zone and including afluid pressure regulator and flow restrictor means connected influid-flow-transmitting relation between said regulator and said firstzone;

c. a conduit for delivering said second fluid for administration to apatient from said second zone; and

d. means for selectively bypassing said flow restrictor means.

3. The combination of claim 1 wherein said container means comprisesfirst and second collapsible containers respectively defining said firstand said second zones and having a pressure-transmitting and movableinterface between said zones.

4. The combination of claim 3 including means confining said containermeans in said pressure-transmitting relation whereby said interface ismovable relative to said confining means in response to fluid flow fromthe second container during collapse thereof.

5. The combination of claim 4 including an indicator having operativeconnection to said interface to move therewith.

6. The combination of claim 1 wherein said first fluid delivery meansincludes a liquefied gas container having an outlet in communicationwith said pressure regulator.

7. The combination of claim 6 including liquefied CO in said liquefiedgas container.

8. The combination of claim 1 wherein said flow restrictor meansincludes multiple restrictors mounted for selective connection in saidfluid-flow-transmitting relation.

9. The combination of claim 8 wherein each of said multiple restrictorscomprises a porous plug.

10. In parenteral liquid administration apparatus, the combinationcomprising:

a. container means having a first zone to receive a presssurized firstfluid and a second zone for a supply of a deliverable second fluid, saidzones extending in such confined and pressure-transmitting relation thatthe second fluid remains pressurized by the first fluid as the secondfluid zone diminishes and the first fluid zone expands;

b. means to deliver said first fluid to said first zone and including apressure regulator and first variable flow restrictor means connected inflow-transmitting relation between said regulator and said first zone;said flow restrictor means having selector means for providing apredetermined but variable pressure drop/flow rate characteristic; and

c. means to deliver said second fluid for administration to a patientfrom said second zone and including a conduit and a second flowrestrictor means connected in flowtransmitting relation with saidconduit;

d. said restrictors characterized in that the first fluid pressure dropacross said first restrictor means substantially exceeds the secondfluid pressure drop across said second restrictor means whereby thesecond fluid flow rate in said conduit is maintained substantiallyuniform and independent of normal gravity induced pressure fluctuations.

11. In parenteral liquid administration apparatus, the combinationcomprising:

a. container means having a first zone to receive a pressurized firstfluid and a second zone for a supply of a deliverable second fluid, saidzones extending in such confined and pressure-transmitting relation thatthe second fluid remains pressurized by the first fluid as the secondfluid zone diminishes and the first fluid zone expands;

b. means to deliver said first fluid to said first zone and including apressure regulator and first flow restrictor means connected inflow-transmitting relation between said regulator and said first zone;

c. means to deliver said second fluid for administration to a patientfrom said second zone and including a conduit and a second flowrestrictor means connected in flowtransmitting relation with saidconduit;

cl. said restrictors characterized in that the first fluid pressure dropacross said first restrictor means substantially exceeds the secondfluid pressure drop across said second restrictor means whereby thesecond fluid flow rate in said conduit is maintained substantiallyuniform and independent of normal gravity induced pressure fluctuations;and

e. means for selectively bypassing said second flow restrictor means.

112. The combination of claim 10 wherein said container means comprisesfirst and second collapsible containers respectively defining said firstand second zones and having a pressure-transmitting and movableinterface between said zones.

13. The combination of claim 12 including means confining saidcontainers in said pressure-transmitting relation whereby said interfaceis movable relative to said confining means in response to fluid flowfrom the second container during collapse thereof.

14. The combination of claim 13 including an indicator having operativeconnection to said interface to move therewith.

15. The combination of claim 10 wherein said flow restrictor meansincludes multiple restrictors mounted for selective connection in saidgas-flow-transmitting relation.

16. The combination of claim 15 wherein each of said multiplerestrictors comprises a porous plug.

17. The combination of claim 10 including a bypass connectable betweensaid regulator and said first zone and including other flow restrictormeans of lower flow resistance than said first flow restrictor means inseries with said bypass and characterized that said first fluid israpidly flowable to said first zone to pressurize same to a levelsubstantially equal to the pressure normally at the outlet side of saidfirst flow restrictor means when said bypass is not connected.

18. The combination of claim 17 wherein said other flow restrictor meansincludes third flow restrictor means and fourth flow restrictor means inseries, said first zone being connected in flow-transmitting relation toa point between said third and fourth flow restrictor means with saidthird restrictor means being in parallel with said first restrictormeans, the ratio of the flow resistance of said first flow restrictormeans to said third flow restrictor means being the same as the ratio ofthe flow resistance of said second restrictor means to said fourthrestrictor means.

19. The combination of claim 17 including valve means to selectivelyconnect said bypass between said regulator and said first zone.

20. The combination of claim 10 wherein said second restrictor meanscomprises a porous plug.

21. The combination of claim 4 wherein said collapsible containerconfining means comprises a housing having interconnected sections thatare relatively separable to permit replacement of said second container,said conduit extending from said second container to move therewithduring collapse thereof, and the housing wall containing an opening topass said conduit and permit said movement thereof.

22. The combination of claim 21 wherein said opening is at one end ofthe housing, and said pressure regulator and said restrictor means areat one side of the housing and enclosed therein.

23. The combination of claim 21 wherein said restrictor means and saidpressure regulator are contained within said housing, and said housingsections have hinge interconnection.

24. The combination of claim 1 and further including flowsensing meansfor indicating fluid flow within the apparatus.

25/1 he combination of claim 24 wherein said sensing means is locatedwithin said conduit. I

26. A combination as set forth in claim 2, mcludmg pressure-responsivemeans for inhibiting said means for selectively bypassing said flowrestrictor means when the pressure at said first zone exceeds apredetermined value.

27. A combination as set forth in claim 3, wherein said container meanscomprise a flexible bag.

28. The combination of claim 10 wherein said second flow restrictormeans is connected to be removable from said flowtransmitting relation.

1. In parenteral liquid administration apparatus, the combinationcomprising: a. container means having a first zone to receive apressurized first fluid and a second zone for a supply of a deliverablesecond fluid, said zones extending in such confined andpressure-transmitting relation that the second fluid remains pressurizedby the first fluid as the second fluid zone diminishes and the firstfluid zone expands; b. means to deliver said first fluid to said firstzone and including a fluid pressure regulator and variable flowrestrictor means connected in fluid-flow-transmitting relation betweensaid regulator and said first zone; said flow restrictor means havingselector means for providing a predetermined but variable pressuredrop/flow rate characteristic; and c. a conduit for delivering saidsecond fluid for administration to a patient from said second zone. 2.In parenteral liquid administration apparatus, the combinationcomprising: a. container means having a first zone to receive apressurized first fluid and a second zone for a supply of a deliverablesecond fluid, said zones extending in such confined andpressure-transmitting relation that the second fluid remains pressurizedby the first fluid as the second fluid zone diminishes and the firstfluid zone expands; b. means to deliver said first fluid to said firstzone and including a fluid pressure regulator and flow restrictor meansconnected in fluid-flow-transmitting relation between said regulator andsaid first zone; c. a conduit for delivering said second fluid foradministration to a patient from said second zone; and d. means forselectively bypassing said flow restrictor means.
 3. The combination ofclaim 1 wherein said container means comprises first and secondcollapsible containers respectively defining said first and said secondzones and having a pressure-transmitting and movable interface betweensaid zones.
 4. The combination of claim 3 including means confining saidcontainer means in said pressure-transmitting relation whereby saidinterface is movable relative to said confining means in response tofluid flow from the second container during collapse thereof.
 5. Thecombination of claim 4 including an indicator having operativeconnection to said interface to move therewith.
 6. The combination ofclaim 1 wherein said first fluid delivery means includes a liquefied gascontainer having an outlet in communication with said pressureregulator.
 7. The combination of claim 6 including liquefied CO2 in saidliquefied gas container.
 8. The combination of claim 1 wherein said flowrestrictor means includes multiple restrictors mounted for selectiveconnection in said fluid-flow-transmitting relation.
 9. The combinationof claim 8 wherein each of said multiple restrictors comprises a porousplug.
 10. In parenteral liquid administration apparatus, the combinationcomprising: a. container means having a first zone to receive apressurized first fluid and a second zone for a supply of a deliverablesecond fluid, said zones extending in such confined andpressure-transmitting relation that the second fluid remains pressurizedby the first fluid as the second fluid zone diminishes and the firstfluid zone expands; b. means to deliver said first fluid to said firstzone and including a pressure regulator and first variable flowrestrictor means connected in flow-transmitting relation between saidregulator and said first zone; said flow restrictor means havingselector means for providing a predetermined but variable pressuredrop/flow rate characteristic; and c. means to deliver said second fluidfor administration to a patient from said second zone and including aconduit and a second flow restrictor means connected inflow-transmitting relation with said conduit; d. said restrictorscharacterized in that the first fluid pressure drop across said firstrestrictor means substantially exceeds the second fluid pressure dropacross said second restrictor means whereby the second fluid flow ratein said conduit is maintained substantially uniform and independent ofnormal gravity induced pressure fluctuations.
 11. In parenteral liquidadministration apparatus, the combination comprising: a. container meanshaving a first zone to receive a pressurized first fluid and a secondzone for a supply of a deliverable second fluid, said zones extending insuch confined and pressure-transmitting relation that the second fluidremains pressurized by the first fluid as the second fluid zonediminishes and the first fluid zone expands; b. means to deliver saidfirst fluid to said first zone and including a pressure regulator andfirst flow restrictor means connected in flow-transmitting relationbetween said regulator and said first zone; c. means to deliver saidsecond fluid for administration to a patient from said second zone andincluding a conduit and a second flow restrictor means connected inflow-transmitting relation with said conduit; d. said restrictorscharacterized in that the first fluid pressure drop across said firstrestrictor means substantially exceeds the second fluid pressure dropacross said second restrictor means whereby the second fluid flow ratein said conduit is maintained substantially uniform and independent ofnormal gravity induced pressure fluctuations; and e. means forselectively bypassing said second flow restrictor means.
 12. Thecombination of claim 10 wherein saId container means comprises first andsecond collapsible containers respectively defining said first andsecond zones and having a pressure-transmitting and movable interfacebetween said zones.
 13. The combination of claim 12 including meansconfining said containers in said pressure-transmitting relation wherebysaid interface is movable relative to said confining means in responseto fluid flow from the second container during collapse thereof.
 14. Thecombination of claim 13 including an indicator having operativeconnection to said interface to move therewith.
 15. The combination ofclaim 10 wherein said flow restrictor means includes multiplerestrictors mounted for selective connection in saidgas-flow-transmitting relation.
 16. The combination of claim 15 whereineach of said multiple restrictors comprises a porous plug.
 17. Thecombination of claim 10 including a bypass connectable between saidregulator and said first zone and including other flow restrictor meansof lower flow resistance than said first flow restrictor means in serieswith said bypass and characterized that said first fluid is rapidlyflowable to said first zone to pressurize same to a level substantiallyequal to the pressure normally at the outlet side of said first flowrestrictor means when said bypass is not connected.
 18. The combinationof claim 17 wherein said other flow restrictor means includes third flowrestrictor means and fourth flow restrictor means in series, said firstzone being connected in flow-transmitting relation to a point betweensaid third and fourth flow restrictor means with said third restrictormeans being in parallel with said first restrictor means, the ratio ofthe flow resistance of said first flow restrictor means to said thirdflow restrictor means being the same as the ratio of the flow resistanceof said second restrictor means to said fourth restrictor means.
 19. Thecombination of claim 17 including valve means to selectively connectsaid bypass between said regulator and said first zone.
 20. Thecombination of claim 10 wherein said second restrictor means comprises aporous plug.
 21. The combination of claim 4 wherein said collapsiblecontainer confining means comprises a housing having interconnectedsections that are relatively separable to permit replacement of saidsecond container, said conduit extending from said second container tomove therewith during collapse thereof, and the housing wall containingan opening to pass said conduit and permit said movement thereof. 22.The combination of claim 21 wherein said opening is at one end of thehousing, and said pressure regulator and said restrictor means are atone side of the housing and enclosed therein.
 23. The combination ofclaim 21 wherein said restrictor means and said pressure regulator arecontained within said housing, and said housing sections have hingeinterconnection.
 24. The combination of claim 1 and further includingflow-sensing means for indicating fluid flow within the apparatus. 25.The combination of claim 24 wherein said sensing means is located withinsaid conduit.
 26. A combination as set forth in claim 2, includingpressure-responsive means for inhibiting said means for selectivelybypassing said flow restrictor means when the pressure at said firstzone exceeds a predetermined value.
 27. A combination as set forth inclaim 3, wherein said container means comprise a flexible bag.
 28. Thecombination of claim 10 wherein said second flow restrictor means isconnected to be removable from said flow-transmitting relation.